Iatrogenic intracranial pseudoaneurysms: neuroradiological and therapeutical considerations, including endovascular options.

Intracranial pseudoaneurysms represent a potentially fatal complication of intracranial surgery. Our purpose is to describe their neuroradiological characteristics, prognostic features and possible treatment. Eight cases of postsurgical intracranial pseudoaneurysms have been observed at our institution since 1988. Four were observed following transsphenoidal (TS) surgery and four after pterional craniotomies. Two types of iatrogenic pseudoaneurysms were observed: "fusiform", probably due to weakening of the adventitia during surgical peeling of the tumour from the artery (three cases) and "saccular", occurring after a more focal or complete laceration of the vessel (five cases), more often after TS surgery. A thorough preoperative neuroradiological examination may identify anatomical conditions at risk for development of this severe complication. Postoperative neuroradiological follow-up is mandatory in cases in which unusual bleeding has occurred during the perioperative period, but absence of bleeding does not exclude the possible development of a pseudoaneurysm. Endovascular treatment of pseudoaneurysms represents a safe and durable procedure, specifically in those cases in which damage to the carotid siphon occurred during TS surgery.

Neuroradiological features of vertigo.

The diagnostic pathway in a patient with vertigo starts with the accurate evaluation of medical history followed by a general physical and neurological examination. This step can often lead to the identification of the correct cause of the disease or, at least, to a distinction between peripheral and central vertigo. Neuroradiological investigations have to be considered as elective diagnostic procedures and include: computed tomography (CT), magnetic resonance (MR), MR angiography (MRA), angiography. For the diagnosis of peripheral vertigo, benign paroxysmal positional vertigo, labyrinthitis, Meniere disease, perilymphatic fistula, local trauma, toxic labyrinthitis, acute otitis media and chronic middle ear effusion,the role of imaging techniques is controversial. CT and MR are performed to rule out other pathologies and to confirm the diagnosis. Increased resolution and application of special MR sequences enhancing the intralabyrinthine fluids have enabled more detailed analysis of labyrinthine structures and pathology. Both T2 and T1 contrast sequences are necessary. A high resolution CT study is required when otitis media is suspected and in the follow-up of post-traumatic vertigo. The causes of central vertigo are numerous and include: vertebro-basilar circulation vascular events, multiple sclerosis (MS), migraine-associated vertigo, cerebellar and brainstem tumors, CNS infections. Among them cerebrovascular ischemia and multiple sclerosis are the most frequent. In these situations imaging studies become mandatory. CT can diagnose most cerebellar hemorrhages and some cerebellar and brainstem acute ischemia, enhanced MR has proved to be the most sensitive tool to detect posterior fossa lesion. Diffusion-weighted MR can reveal acute ischemic changes before routine MR. There has been evidence that MR angiography, providing angiogram-like images of the intracranial vessels may sometimes avoid invasive angiography. MRA resolution is not as good as traditional angiography and may also be compromised by movements and other artifacts. Selective angiography of the posterior circulation is often indicated for therapeutic decisions.